Groundwater Pollution Vulnerability Assessment: Assessing groundwater pollution potential from nitrogen fertilizer using geographic information system

A Point Count System model, DRASTIC, was used to assess the groundwater pollution potential from nitrogen fertilizers in Ludhiana district of Punjab, India. Thematic maps of the seven parameters of the model i.e. depth to water table, recharge, aquifer media, soil, topography, impact of vadose zone and hydraulic conductivity were prepared in a geographic information system (GIS) environment to obtain nitrogen pollution potential indexes based on the consumption of nitrogenous fertilizers. The model was calibrated and validatedfor the region.Statistical analysis showed good agreement between model computed and observed values of Nitrate-N concentration. The model was used to predict the future scenario. As per model prediction, the area under critical value may reach up to 50730 ha by the year 2012. Machhiwara, Sidhwan bet and Ludhiana-2 blocks of the district will be severely affected.To prevent this grave situation, the areas having higher nitrate pollution potential index may be enforced with restricted fertilizer use and be made the focus of attention for preventing contamination of the underlying groundwater sources.